The situation also worsened the widespread use of pesticides in agriculture. Their use has a negative impact on all groups of soil organisms including the earthworms which has resulted in a significant reduction of their biomass. The remains of grown with pesticides plants decompose in the soil conducing the reduce of the mass of earthworms. Furthermore, many pesticides destroy the natural enzymes and complexes of humic substances with metals which are necessary for plant life. This disrupts the natural balance of the soil leading to decrease of humus content, of mobile forms of phosphorus,of potassium and of other elements in it. It has long been known that chemical fertilizers and pesticides by their regular use, especially in excessive doses (this fact is quite common) are intensely polluting. Many of them are toxic and dangerous to humans and animals.

The most effective way to increase the biological efficiency of agriculture appeared to be the use of earthworms. Even the ancient researchers paid attention to the earthworm, this eternal worker, which was called at the time as the main plow of the soil. In ancient Egypt, the protection of earthworms was placed at such level that the perpetrators of their extinction were facing the death penalty. In ancient times, farmers determined the fertility of the soil by the presence of earthworms in it.

The work performed by billions of worms in the soil is huge; worms loosen the soil in search of food; they absorb soil lumps, which are rich in waste organic matters, and, therefore, in microorganisms. They overcome great distances underground doing this. On average, over the summer the worm is capable of making to 1 km of steps. If there are 50 or more worms in 1 square. meter of the soil, it  can be considered as the good soil. Earthworms do not just loosen the soil, they produce along with micro-organisms a solid structure from it, which is not prone to erosion. The activities of earthworms in the soil is not limited to mixing, transfering and digging the soil. The soil changes chemically and structurally when passing through the worm's digestive tract. The transformation of dead organic matter by microorganisms is strongly shifted towards the accumulation of organic matter in soil, namely the humification of organic matter, if the worms have worked on the soil. Humic substances  are an ideal living environment for beneficial microorganisms.

Soluble humic substances structure the water in the soil, surpress the activity of phytopathogens. They also are contemporaneously great natural biostimulants for plants. Humic acids form insoluble compounds with heavy metals and radionuclides and prevent from getting them into the plants. This is the natural mechanism of protection of all life on the Earth from heavy metal poisoning. Humic substances are not only a habitat for microorganisms, but also food supply for them and for the plants. In addition, they are black what also gives a darker color to the soil. This greatly increases the soil absorption of heat and light which means the accumulation and transfer of solar energy to the plants.

There is no doubt that the acquisition methods of maximum use of earthworms activity can contribute to make any soil high-fertile.

Domesticated earthworms (the term is usually used for animals)  are a special breed of earthworms, which are specially fed and watered in order to increase their natural size and to accelerate the natural rate of reproduction. They are no bigger than the natural "wild" red or manure (compost) worms, but they retain the vitality and strength, an attractive color and fertility.